iframe 随页面自动适应大小

<script language="javascript">
  var iframeids = ["showmain"];
  var iframehide = "yes";
  
  function dyniframesize() {
   var dyniframe = new Array();
   for (i = 0; i < iframeids.length; i++) {
   
    if (document.getElementById) {
     dyniframe[dyniframe.length] = document.getElementById(iframeids[i]);
     if (dyniframe[i] && !window.opera) {
      dyniframe[i].style.display = "block";
      if (dyniframe[i].contentDocument && dyniframe[i].contentDocument.body.offsetHeight) {
       dyniframe[i].height = dyniframe[i].contentDocument.body.offsetHeight;
      } else {
       if (dyniframe[i].Document && dyniframe[i].Document.body.scrollHeight) {
        dyniframe[i].height = dyniframe[i].Document.body.scrollHeight;
       }
      }
     }
    }
    if ((document.all || document.getElementById) && iframehide == "no") {
     var tempobj = document.all ? document.all[iframeids[i]] : document.getElementById(iframeids[i]);
     tempobj.style.display = "block";
    }
   }
  }
  function resize() {
   dyniframesize();
   parent.dyniframesize();
  }
 
  if (window.addEventListener) {
   window.addEventListener("load", dyniframesize, false);
  } else {
   if (window.attachEvent) {
    window.attachEvent("onload", dyniframesize);
   } else {
    window.onload = dyniframesize;
   }
  }
  
  </script>

 

<iframe marginheight=0 marginwidth=0 frameborder=0 width=100% style="overflow-x:hidden;" height=650 scrolling=no src="" name=showmain id=showmain onload="resize();">不能正常显示</iframe>